Evaluation of Visual Performance when Using Incandescent, Fluorescent, and LED Machine Lights in Mesopic Conditions

This experiment investigated the effects of different machine mounted area lighting technologies on visual performance. The primary objective was to conduct a comparative evaluation of the lighting technologies based on the visual performance of thirty-six human subjects in a simulated underground mine environment. Incandescent (Incand), fluorescent (Fluor), and light-emitting diode (LED) technologies were used to create four lighting combinations. Visual performance was quantified for the detection of movement in the peripheral field of view and the identification of ground hazards. Measurements were made of the speed [response time measured in milliseconds (ms)], the accuracy (the number of targets and objects missed), and the subjective discomfort rating of the glare experienced for each lighting combination. A secondary objective explored the effects of aging on visual performance. The results indicate that lighting combinations which consisted of LED area lights significantly improved visual performance for the detection of hazards found in the peripheral field of view, as well as those found on the ground. They furthermore, indicate that age plays a significant role in visual performance.2009893

Light Res Technol

Proper lighting plays a critical role in enabling miners to detect hazards when operating a roof bolter, one of the most dangerous mining machines to operate; however, there has not been any lighting research to address the walk-thru type of roof bolter commonly used today. To address this, the Saturn light was designed to directly address walk-thru roof bolter safety by improving trip hazard illumination. The visual performances of 30 participants that comprised three age groups were quantified by measuring each participant's visual performance in detecting trip objects positioned on the two floor locations within the machine's interior working space. The lighting conditions were the existing compact fluorescent lights (CFLs) and the Saturn LED area light developed by NIOSH researchers. Three intensities of the Saturn lights were used, 100%, 75%, and 50%, all of which resulted in better visual performance, and up to a 48% reduction in average trip detection time compared to the CFL. For the Saturn trip object miss rates were <0.5% for all age groups in contrast to the CFL, which ranged between 32.5% for the youngest group and 50.4% for the oldest group.CC999999/Intramural CDC HHS/United States2020-08-01T00:00:00Z30174557PMC61126068081vault:3256

IEEE Trans Ind Appl

Lighting regulations for luminance in U. S. coal mines are verified in the field by using a luminance photometer calibrated to the Standard Illuminant A light source. Significant measurement errors can exist when measuring light sources that are dissimilar to light sources used to calibrate the photometer. This paper quantifies the measurement errors when measuring these dissimilar light sources commonly used in U.S. underground coal mines-an LED, a CFL with a clear cover, a CFL with an amber cover, and a tungsten halogen. The impact of photometer quality was also evaluated. Three different luminance measuring instruments of high, medium, and low quality were compared-a PR-650, LS-100, and PMEX, respectively. The PMEX was under evaluation for measuring luminance compliance in U.S. underground coal mines. The PR-650 was used as the referent to which the other photometers were compared. The PMEX error ranged from -17.0% to -26.5% with the highest error for the amber CFL. The LS-100 closely matched the luminance measurement for the LED and halogen; however, it had a percent error of -10.4% for the amber CFL. After the initial experiment, MSHA made improvements to the PMEX resulting in the PMEX-MSHA. The experiment was replicated using the new photometer and the newer PR-670. After repeating the experiment, the measurement errors ranged from -16% to -19% for the PMEX-MSHA, thus indicating an improvement over the PMEX. These results show that the spectral content of a light source and the photometer quality can greatly impact the accuracy of luminance measurement.CC999999/ImCDC/Intramural CDC HHS/United States2019-11-25T00:00:00Z31768079PMC6876124696

Min Metall Explor

Researchers from the National Institute for Occupational Safety and Health (NIOSH) developed a light-emitting diode (LED) area luminaire called the Saturn and conducted a laboratory study using a Fletcher High Dual-boom Mast Feed (HDDR) roof bolting machine. The Saturn luminaire was designed to (1) enhance floor illumination to enable better detection of trip hazards in the interior spaces of a roof bolter and (2) reduce glare that has typically been an issue of concern on roof bolters. This paper reports on the results of achieving the second objective. The existing roof bolter lighting was the baseline and was compared with three versions of the Saturn luminaire relative to light intensity (100%, 75%, and 50%). Discomfort and disability glare data were obtained from 30 participants that comprised three age groups. Discomfort glare perceptions were obtained using the De Boer rating scale, and disability glare was quantified by using Mars Letter Contrast Sensitivity tests. Discomfort glare was reduced at least 3 levels with all Saturn versions. Also, a predictive model was used to estimate discomfort glare, and the results were similar. Disability glare was the least for the Saturn's 50% intensity, and all Saturn versions had significantly less disability glare than with the baseline lighting. Veiling luminance was calculated and used as another indicator of disability glare. Veiling luminance was 28 to 42 times greater with the baseline lighting as compared with that of the Saturn lighting. Lastly, visibility levels were calculated. The Saturn versions were 4 to 6.5 times better in terms of visibility level.CC999999/ImCDC/Intramural CDC HHS/United States2020-07-17T00:00:00Z32685916PMC73676748043vault:3576

Application of Solar Energy for Lighting in Opencast Mines

Proper illumination in mines is a major requirement for un-interrupted production and improved safety. Most of the mines currently use conventional lighting systems. The energy source for such lighting systems are either electric or diesel power. The price of fossil fuel and diesel are increasing rapidly, which is responsible for increased price of power generation and cost of illumination. Therefore an alternative source like solar energy is a necessary requirement. The illumination level of mines can be improved by increasing the power output of a solar panel, the light intensity of solar panel being directly proportional to power output of solar panel. Solar energy could be a good choice of power generation, since the cost of solar panels decreasing rapidly in the past few years. Moreover, solar energy has also become more efficient as compared to other source of energy

Optimal Roof Coverage and Identification of Potential Roof Problems in Underground Coal Mines Using LED Lighting

The popularity and implementation of light emitting diode (LED) lighting have increased drastically over recent years into both residential and industrial applications. However, due to MSHA permissibility requirements, LED lighting is not currently being fully utilized in underground coal mining. While previous research has focused on examining the benefits that LED lighting possesses over other common light sources, very few have been done to find the optimum configuration to illuminate underground excavations better for the safety of the miners. In this research, multiple experiments were conducted to evaluate the potential impacts LED lighting can have on underground mine safety. The optimal light setup that provided the most roof coverage was found to be between 5 and 7 feet of separation, which is similar to what is usually used on roof bolting machines. It was also determined that LED lighting performs well in terms of discontinuity identification compared to what is commonly used in underground coal mining. The results of this research will serve as a design parameter for lighting manufacturers to use. These tests were done to simulate possible lighting locations on a roof bolting machine, but the results can be employed for other underground equipment as well

Min Metall Explor

Nonfatal injuries from slips, trips, and falls (STF) that occur at surface mines can result from inadequate lighting. Mobile equipment operators are among the occupations associated with the nonfatal incidents reported to the U.S. Mine Safety and Health Administration (MSHA). In addition, getting on/off the equipment (ingress/egress) frequently adds to the highest proportion of nonfatal incidents. Accordingly, researchers at the Pittsburgh Mining Research Division (PMRD), National Institute for Occupational Safety and Health (NIOSH) conducted a field study to investigate lighting on haul trucks and wheel loaders with regard to glare and illuminance levels recommended by the Illuminating Engineering Society (IES). The objective was to determine whether two light-emitting diode (LED) area luminaires-a Mr. Beams\uae (model MB390 Ultrabright) (area luminaire-1) and a NIOSH-developed Saturn (custom-designed for a mine roof bolter study) (area luminaire-2)-could complement a headlamp luminaire. Measured levels of visual tasks, with the headlamp alone and the area luminaires plus the headlamp, demonstrated that illuminance met or exceeded IES-recommended levels. Nevertheless, the area luminaires illuminated a much broader area, which is key to increasing hazard awareness. Discomfort and disability glare were lower with area luminaire-1 than with area luminaire-2. Differences in glare were more noticeable for newer models of haul trucks and loaders featuring updated ingress/egress system designs. This study demonstrates that commercially available luminaires, such as area luminaire-1, are capable of complementing headlamp lighting, and can thus improve a miner's ability to detect and avoid STF hazards.CC999999/ImCDC/Intramural CDC HHSUnited States/2022-07-13T00:00:00Z35836960PMC927855111624vault:4296

Optimising Light Source Spectrum to Reduce the Energy Absorbed by Objects

Light is used to illuminate objects in the built environment. Humans can only observe light reflected from an object. Light absorbed by an object turns into heat and does not contribute to visibility. Since the spectral output of the new lighting technologies can be tuned, it is possible to imagine a lighting system that detects the colours of objects and emits customised light to minimise the absorbed energy. Previous optimisation studies investigated the use of narrowband LEDs to maximise the efficiency and colour quality of a light source. While these studies aimed to tune a white light source for general use, the lighting system proposed here minimises the energy consumed by lighting by detecting colours of objects and emitting customised light onto each coloured part of the object. This thesis investigates the feasibility of absorption-minimising light source spectra and their impact on the colour appearance of objects and energy consumption. Two computational studies were undertaken to form the theoretical basis of the absorption-minimising light source spectra. Computational simulations show that the theoretical single-peak spectra can lower the energy consumption up to around 38 % to 62 %, and double-peak test spectra can result in energy savings up to 71 %, without causing colour shifts. In these studies, standard reference illuminants, theoretical test spectra and coloured test samples were used. These studies are followed by the empirical evidence collected from two psychophysical experiments. Data from the experiments show that observers find the colour appearance of objects equally natural and attractive under spectrally optimised spectra and reference white light sources. An increased colour difference, to a certain extent, is found acceptable, which allows even higher energy savings. However, the translucent nature of some objects may negatively affect the results

Museum Lighting - an holistic approach

Among the environmental parameters that effect exhibited artifacts, light is the most complex and the only essential for the observer as to appreciate the artifacts, thus being one of the most critical variables of art exposure. Research on strategies for energy saving and the renovation of light destined to Heritage is examined by daylight admission and Light-Emitting Diode (LED) technology. The extended review of the literature presented below, over museum lighting, evidenced the parallel advance of lighting principles with lighting design, concerning what determines visual quality and perception. Lighting quality is an interdisciplinaryfield of research affecting human activity and under a requested task, visual performance, while at the same time improving well-being. In this sense, the role of the lighting designer is to match and rank human needs with economic and environmental aspects as to architectural principles and to translate the results into a feasible design and an efficient installation. Quality factors for art exposure, involving color fidelity and damage, along with visual perception necessitate of useful metrics through established criteria. The challenge for the museum for a holistic design of natural and artificial light is still missing of substantial metrics, even though recent findings provide some insight on the workflow to establish. Luminance-based design metrics and contrast criteria are used in this study as key strategies for museum lighting, combining comfort and viewing fine arts through advanced computer rendering. The exploration of the transition inside a daylit gallery where moving in the museum environment offers an experience for a series of adaptation changes through photopic, mesopic and dark-adapted scotopic function, along with change on the sensitivity of the spectrum. The luminance appearance and the transition adaptation in the museum field lack of research examination; the relationship of prescriptive requirements and luminance- based design has been explored initially in the field of road lighting, where the relative visual performance has been evidenced to be in the center of the CIE standard for tunnel lighting. Daylight simulation via climate-based modeling, introducing daylight filters as solar shading devices, has been proposed as the object of experimental research, connecting light “filtering” with luminance; this workflow could be applied in several fields of research considering museum environment and give responses in the preservation of artwork involving daylight. The subject of this thesis is the proposal of a ‘trama’ surface installed on windows to reduce and control daylight, studying how energy and conservation targets can be achieved. New light sources and smart control systems will integrate to a holistic approach for museum lighting design